Regenerative dynamometer for use with an electrical submersible pump

Abstract

A dynamometer is used to dynamically evaluate an electrical submersible pump (“ESP”) motor while both are inside of a well. The dynamometer includes a ESP dyno that is mechanically coupled to the ESP motor. The ESP motor and ESP dyno can be a permanent magnet motor or an induction motor, and can have the same or similar values of inertia. Energy absorbed by the ESP dyno can be regenerated as electricity that is transmitted back to a power source, or converted to heat energy in a resistive load bank.

What is claimed is: 
     
         1 . A method of evaluating an electrical submersible pump (“ESP”) motor comprising:
 forming a test assembly by coupling an output of the ESP motor with another ESP motor that defines an ESP dyno; 
 deploying the test assembly into a well; 
 energizing the ESP motor; 
 monitoring the test assembly; and 
 qualifying the ESP motor for use in lifting liquids from a wellbore based on the step of monitoring. 
 
     
     
         2 . The method of  claim 1 , wherein the ESP motor and ESP dyno comprise motors selected from the group consisting of a permanent magnet motor and an induction motor. 
     
     
         3 . The method of  claim 1 , wherein an inertia of the ESP dyno is approximately the same as an inertia of the ESP motor. 
     
     
         4 . The method of  claim 1 , further comprising monitoring an output from the ESP dyno. 
     
     
         5 . The method of  claim 4 , wherein energizing the ESP motor causes rotation of a shaft in the ESP dyno, and wherein the output from the ESP dyno comprises electricity that is generated by rotation of the shaft, the method further comprising connecting the output of the ESP dyno to a resistive load bank and varying a magnitude of resistance in the resistive load bank. 
     
     
         6 . The method of  claim 1 , where monitoring the test assembly comprises monitoring operating information selected from the group consisting of an amount of electricity flowing to the ESP motor, an amount of electricity flowing from the ESP dyno, a torque exerted by the ESP motor, and combinations thereof. 
     
     
         7 . The method of  claim 6 , wherein the torque is monitored with a torque cell coupled between the ESP motor and ESP dyno. 
     
     
         8 . The method of  claim 1 , wherein the ESP dyno is downhole of the ESP motor. 
     
     
         9 . The method of  claim 1 , further comprising regenerating energy delivered to the ESP motor by capturing output from the ESP dyno. 
     
     
         10 . A system for evaluating an electrical submersible pump (“ESP”) motor comprising:
 an ESP dyno selectively disposed in a test well and having a shaft that is rotationally coupled to a shaft of the ESP motor, wherein the ESP dyno comprises another ESP motor; 
 a power source in electrical communication with the ESP motor; and 
 a sensor attached to an output of the ESP dyno. 
 
     
     
         11 . The system of  claim 10 , further comprising a hanger selectively coupled between an uphole end of the ESP and a structure mounted over an opening of the test well. 
     
     
         12 . The system of  claim 10 , further comprising a coupling selectively attached between a downhole end of the ESP motor and an uphole end of the ESP dyno. 
     
     
         13 . The system of  claim 12 , wherein the coupling comprises a torque cell that is responsive to a torque exerted between the ESP motor and ESP dyno when the ESP motor is energized. 
     
     
         14 . The system of  claim 10 , wherein the sensor is sensitive to an amount of electricity flowing to the ESP motor, an amount of electricity flowing from the ESP dyno, a torque exerted by the ESP motor, and combinations thereof. 
     
     
         15 . The system of  claim 10 , wherein an output of the ESP dyno is regenerated to the power source. 
     
     
         16 . The system of  claim 10 , further comprising a resistive load bank in electrical communication with an output of the ESP dyno, wherein a resistance through the resistive load bank is variable. 
     
     
         17 . The system of  claim 10 , wherein the ESP motor and ESP dyno comprise a motor type selected from the group consisting of a permanent magnet motor and an induction motor.